This paper proposes an interleaved LLC resonant converter with cascaded voltage doubler circuits for deeply depleted PEV battery charging. The use of voltage double circuits extends the operating range of converter by mitigating the effects of transformer’s parasitic capacitors. The converter has two modes of operation: simultaneous and independent. In former mode both interleaving converters operate together at same frequency and in later mode only one converter operates. In former mode, it yields twofold higher gain compared to later one. Thus, operation with combined mode changing and frequency control results in wider output voltage range. For confirmation, a laboratory prototype rated at input dc voltage of 400V and output power of 1.5kW is designed, and implemented. The results obtained from the prototype show that converter achieves a wide output voltage range of 100V–420V when operated in simultaneous mode with simple frequency control and an output voltage range of 50 –100V in the independent mode. With combined frequency and mode changing control it achieves an output range of 50V–420V. The peak efficiency of converter was measured to be 95.65% at a peak power of 1.5 kW. Thus, the proposed converter is suitable for the dc-dc stage of on-board PEV battery charger.

This paper proposes an HB-2LLC resonant converter with hybrid rectifier to realize wide output voltage control range (100-420 V) for plug-in electric vehicle (PEV), on-board battery charging. The converter has two resonant tanks, each connected with one of the two primary windings of transformer. The two resonant tanks are alternately fed from 400 V dc source by operating two power switches, each with a half switching cycle. The hybrid rectifier connected at the secondary of transformer can be operated as a bridge rectifier or voltage doubler. It operates as a bridge rectifier to achieve output voltage range of 100-250 V for deeply depleted battery charging, and as a voltage doubler to achieve output voltage range of 250-420 V for normal battery charging. To validate the operation and performance of converter, a laboratory prototype rated at 1.5 kW output power and 400 V input dc voltage was designed and implemented. The presented results show that with combined mode changing and frequency control, the converter achieves an output voltage range of 100-420 V. The peak efficiency of converter was measured to be 95.21% at a peak power of 1.5 kW. Thus, the proposed converter is suitable for PEV battery charging application.